Dialog: dragging needs to generate _onBlur

Description

Running Firefox or Safari, load dijit/tests/test_Dialog.html and click to open the first dialog.
Click to focus either the DateTextBox? or TimeTextBox? so that the popup appears. Now mousedown on the Dialog titlebar and drag it somewhere. You'll notice that the popup stays put. The problem is that _onBlur is not being called. It works correctly on IE. It also fails on ComboBox? widgets. #104035